? about hypo salinity.

[Harpo]

I was wondering, on a FO. tank, would it cause any problems to leave your tank at hypo salinity levels, such as 1.015? Keeping n mind the tank does not support any other type of life.
Your opinions are appreciated. THANKS.

Bill

[Alice]

Well, that sounds a little low to be keeping fish on a permanent basis and 1.015 is not low enough to kill off cryptocaryn parasites. 1.019 might be a more acceptable range at which to keep the fish. I'm not sure at which level the bacteria die off.

I've never kept an FO, however; so maybe others who have experimented with SG levels will chime in.

Alice

[grazzit]

I know my LFS keeps their FO temporary system at 1.009 (at least if memory serves me they do) and the fish do fine, at least on a temporary basis. I would imagine 1.015 would be fine. I've got a book that mentions reccomended SG for FO systems, I'll dig thru it sometime soon and give ya the #'s if I don't forget........or get too lazy =P

[beach bum]

1.015 is unnecessarily low, like Alice said. Most fish do fine at depressed salinity levels, at least in my limited experience. Sorry I can't give a scientifically proven formula to you, but I keep mine at 1.021 approximately.

Fwiw, I also like a lower temp for my FO, 76-77. The idea being to keep the metabolism down a bit, feed less and keep the water cleaner. Don't know how well it works though! Trying to keep a puffers appetite down is like trying to disprove the existence of gravity.

[Alice]

1.009 is the rock bottom lowest and is used during the hypo salinty treatment for ich and other parasites. Accurate monitoring at low levels of salinity is a must; if it drops below 1.009, you're going to have dead fish.

If the reasoning behind lowered salinity in an FO is to keep parasites at bay, I'd say for overall fish health and maximum protection they'd be better off with at a lower temp than a reef tank, good diet, excellent water params and a big ol' UV.

Just my 2 cents.

Alice

[Harpo]

Thanks, we just finished a bad spell of ich. We are slowly bringing the salinity back up to normal. Unfortunately, we ended up losing our refugium that we ran on this tank during the treatment . Before the ich we were running a refugium, UV, and LR. The tank was copper treated and all items in the refugium were removed, and the LR is slowly in transition. During the period we lost our Bluejaw, Stars and stripes puffer, Naso Tang, Gold Spot Rabbit and a large Green Chromis . The tank is in full recovery now. Thanks again.
Bill

[Alice]

I'm sorry to hear about the loss of your fish

[TerryB10]

Harpo,
Do I understand that you mixed hyposalinity with copper? That is not a good idea and may be the reason for your wipeout. A specific gravity of 1.009 is not actually the lowest that you can keep the fish. It is just a good level that allows a small margin of error between stressing the fish and an ineffective treatment.
Terry B

[Harpo]

We didn't know at the time about mixing the two. The puffer and Bluejaw were just absolutely covered, the Gold spot, and Naso were both totally clear of ich, I believed at the time it was stress. But it was a terrible loss at any rate. Really loved all of them.

Bill

[Alice]

Terry;

How low can you go? (Not that I'd feel inclined to push the envelope too far) And at what SG is the bacteria affected?

Alice

[TerryB10]

We should really talk about salinity rather than specific gravity because the SG is affected by water temperature while salinity is not. I recommend a salinity of 14ppt for treatment. It is probably safe to go as low as 12ppt but there is no reason to take it that low, it's just added risk.
The bacteria that perform denitrification are the same in both freshwater and saltwater aquariums. The only danger, IMO, is changing the salinity (acclimating the bacteria) too quickly. I suggest using four water changes made over two days to bring the salinity to the treatment level. Check the pH and salinity DAILY. Don't forget that practicing quarantine is a cornerstone to long term success in this hobby.
Terry B